Expression of thymidine phosphorylase in human superficial bladder cancer

The purpose of the present paper was to investigate the expression level of thymidine phosphorylase (TPase) in superficial bladder cancer tissues obtained by transurethral resection, and determine whether its expression correlates with tumor recurrence.

From March 1998 to December 2001, 99 patients with superficial bladder cancer were diagnosed and treated at eight affiliated hospitals. Tissue specimens obtained by transurethral resection of superficial bladder cancer (TURBT) were applied to immunohistochemical study using anti-TPase antibody as well as pathological diagnosis. The data were subjected to statistical analysis.

Using MoAb 654-1 as the primary antibody, TPase was clearly stained in human bladder cancer tissues. The maximum TPase level measured by enzyme-linked immunosorbent assay (ELISA) method in normal bladder tissues was 18.7 U/mg protein. The TPase activity was 2.8-fold higher in tumors than in normal bladder samples (P = 0.037). The TPase positivity rates determined by immunohistochemical and ELISA methods were distinctly correlated (P = 0.046). For the recurrence-free rates in pT1 tumors treated by TURBT alone (n = 46), there were no statistically significant differences between Tpase-positive or -negative cases.

The TPase expression determined by ELISA and immunohistochemistry is significantly up-regulated in superficial bladder tumors compared with normal bladder samples. However, TPase expression by immunohistochemistry is not a predictive index of recurrence-free rate for superficial bladder cancer treated with TURBT alone.